Is it possible to have a rough idle due to a bad or about-to-go-bad alternator?
Any thoughts?
Any thoughts?
Rough Idle and Alternator
- Thread starter RJCobra
- Start date
It's definitely possible.
Do you have a CEL?
Has the battery light come on?
Have you checked voltage using a multimeter at the battery and/or datalogged the car?
Cleaned your MAF?
Checked your plugs?
Checked for vacuum leaks?
Checked TPS voltage?
IAC valve working correctly?
Last time fuel filter was replaced?(possibly bad gas, too)
MAF position? (i.e. clocked in the same position it was tuned and facing the right direction)
Made sure there is no leaks POST MAF to ensure no unmetered air is getting into your engine?
I'd start there.
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not saying it isnt possible....but what i will say, is that i am currently on my 4th alt, in a little over 2 years....and a rough idle was NEVER one of the symptoms.
the symptoms were usually - battery light flashing/coming on during WOT pulls...and if it gets bad enough, the radio will cut itself off, the ABS light on the dash will flash (along with a couple of others)...and if you KEEP driving (after it displays the above symptoms) the car will eventually die (once it drains the battery, since the alt is no longer charging). once it dies, it will jump start ok...then you will have about 15 minutes worth of driving before it dies again. fun fun.
never a rough idle tho. at least not for me.
the symptoms were usually - battery light flashing/coming on during WOT pulls...and if it gets bad enough, the radio will cut itself off, the ABS light on the dash will flash (along with a couple of others)...and if you KEEP driving (after it displays the above symptoms) the car will eventually die (once it drains the battery, since the alt is no longer charging). once it dies, it will jump start ok...then you will have about 15 minutes worth of driving before it dies again. fun fun.
never a rough idle tho. at least not for me.
Changed the plugs a few moths back to NGK TR6ix. Smooth idling since then until my battery died. Then the new battery wouldnt charge. Alternator checked out "ok" after replacing the battery cable terminals. Now all is well except for the rough idle. Worse when its been idling for a while, sometimes it drops the rpms so low that it feels like the car's gonna shut off.
This is my 2nd alternator, and I still have never seen the battery light.
Intake, MAF looks ok
Maybe the fuel filter. I'm not sure if I've ever changed it, have 50K miles now.
Sounds more fuel/air/spark related to me, but I have heard of the electrical systems on these cars doing crazy things when the alt is bad or about to go out.
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